SNAFU; high performance 318is build that lives up to the name, Turbo M42 ➞ Turbo M20

[downforce22]

RIP :'( The m42 is such a rad little engine. What are you doing with the m42 setup? ( exhaust manifold, downpipe, etc)

[ForcedFirebird]

At spectoberfest, other BMW owners were able to admire my lovable garbage, and I got a ride in this:





This chump car was built by John at WOT-Tech and painted by a swarm of children. The ride was loads of fun until it broke down after 4 laps, as is my luck.

Sorry about that! Car was loaded on the trailer after the 14hr race and never touched before the event, and the reason I didn't enter the races. Knowing the car was still beat up, didn't want to be causing yellow flags for breakage (plus all my Toyo RR's are toast :/). Come out for the Homstead event in January! I took another spctator for a ride after we fixed the fuel pump, and the exhaust hangers broke, so he only got a couple hot laps too...

[cleanasse30]

Good luck riding out the storm, keep us updated on your swap progress

[Dj Buttchug]

Rip m42

[varg]

Updates!

First, the M42 is finally showing signs of giving up. Every cylinder leaks compression into the cooling system, though no water winds up in the cylinders. Either the head is warped, the MLS head gasket is not sealing to the block correctly or the head is cracked on all cylinders. The gasses that get into the cooling system displace the water into the expansion tank, then the pressure gets too high and it pukes coolant. It has not been overheated since I've had the car. I made this little gadget to keep the system bled, it allows the gasses to escape without losing any coolant.



It works well enough that I was able to make the 200mi+ round trip to spectoberfest without issue.





At spectoberfest, other BMW owners were able to admire my lovable garbage, and I got a ride in this:





This chump car was built by John at WOT-Tech and painted by a swarm of children. The ride was loads of fun until it broke down after 4 laps, as is my luck.

Yesterday, I bought this:



For parts of course. Since the M42 is giving in to age and abuse, it's time to get what I've wanted since I first turbocharged the M42; an M20. It's a slush-o-tragic convertible which means the engine likely hasn't been beat to hell, and it has much lower miles than my M42. I was going to build a stroker M20 but I can't afford that right now, so for now this stock M20B25 is going to get some basic attention, then I will put a nice turbo on it so it can move into its new home in my 318 and start out-doing the M42 right away.



The work on this swap was supposed to start this week, but as I type this a category 4 hurricane is chugging towards my home. Who knows how long this setback will turn out to be.

As much as I knock the M42 for being a flawed and noisy engine, it has earned a place in my heart for putting up with the abuse of making at least twice as much power as it did stock, all of which I used regularly. Since I put the big turbo on I have known two M20s that were bone stock and died a non-timing-belt death, the M42 has served me well and survived despite what I've put it through. Even with the issues it is having now, my car is still driveable and I can still get into full boost for a little fun when I need it.

[econti]

Grey mesh for the centre and some blanking plates and it'll be looking very close to factory. Beaut cooler size though, that's awesome

[Northern]

So much room for activities in an M42 engine bay... between the Z3M rad and the M52, I have zero room for a fan. I only have one because the 16" slim SPAL fits inside the rad support where my condenser used to be.

[Schnitzer318is]

Okay... now I see why you were having a hard time. That intercooler is probably 4x larger than the one I'm running. :)

Nice work getting it to fit in there with the AC components though. I'm sure there was much cursing involved.

[varg]

The intercooler is on and the car is put back together. It was one hell of a process.


Pipes too long.


Cut down and beaded.


My $6 bead forming tool.


I had to cut the bracket off of this AC condenser line and push it back in order to make the IC fit behind the valance, even with all of the cutting. The zip tie is to keep it from vibrating and eventually breaking.


The cut valance.


The cut I made in the bumper hoping for some more air flow to the top of the IC.


The old stack.


And finally, no more stack and a proper electric fan. This is off of a Volvo 940, it's a powerful two speed fan and with the end of the shroud cut off it fits the M42 radiator quite well. I shouldn't have any airflow troubles anymore.


It's a little conspicuous for my taste and even though I never needed them I really liked how the brake ducts looked so I'm bummed that they're gone. I do not like the look of the exposed piping. I also managed to break one of my fog lights, which miffed me. I'm going to get my hands on some fog light blanks and hopefully figure out a way to cleanly block the open hole where the brake ducts once went so I don't have to look at the piping.

[varg]

I think you should consider redoing your intercooler setup to allow room for the stock clutch fan and shroud. On my turbo m20 the temperature is always right around the halfway mark, regardless of whether the ac system is on. As long as your willing to cut up the valence a bit, you can fit the radiator in its stock location, a condenser, slim spal and intercooler with the 2.5 inch pipes running below the headlights.

Unfortunately it's probably impossible to run the stock fan with a setup like mine, even with the intercooler relocated. The IC is too large to mount with the piping routed under the headlights, I attempted to do that recently and it didn't work. With the IC mounted low the piping has to go somewhere, and that somewhere is space the mechanical fan and shroud would occupy. My "new" Volvo 940 E-fan will be adequate. They move air like nobody's business.

Can you low mount the cooler behind the valance?
Alternatively be fucking sick and run a V mount setup and put the condenser in the boot or something

Moving the IC behind the valance has been the plan all along. I just wrapped that job up today, in fact. Boy was it a huge pain in the ass.

I must've missed someone already say this, but maybe it's time for a bigger rad?

I doubt my problem has to do with the radiator's heat rejection capability. We'll soon find out since I've put the radiator back in its rightful place and upgraded my electric fan to the powerful Volvo radiator fan that I've had laying around.

[Northern]

I must've missed someone already say this, but maybe it's time for a bigger rad?

[econti]

Can you low mount the cooler behind the valance?
Alternatively be fucking sick and run a V mount setup and put the condenser in the boot or something

[megu2ice]

I think you should consider redoing your intercooler setup to allow room for the stock clutch fan and shroud. On my turbo m20 the temperature is always right around the halfway mark, regardless of whether the ac system is on. As long as your willing to cut up the valence a bit, you can fit the radiator in its stock location, a condenser, slim spal and intercooler with the 2.5 inch pipes running below the headlights.

[Schnitzer318is]

The thermostat isn't going to change anything here, a 75°C thermostat doesn't flow any more water than an 80°C or 88°C thermostat, it just opens earlier. Thermostat temp doesn't make a lick of difference once you're past it.

True, for some reason that never registered in my head. I remembered though I do run a mostly water/coolant mix. 90/10 maybe with a bottle of water wetter thrown in for good measure. I've actually been meaning to drain everything and throw in BMW's smurf piss to see if it makes a difference.

FWIW, 205°f is not overheating, even for these cars. Many cars are designed to keep coolant temps higher than that bone stock. 230°f is overheating.

Noted, I just don't like to be over center hash at all... that's what I meant by overheating, not actually overheating towards the red part of the gauge. I think 215deg puts me over the middle mark by more than I like if memory serves (I drove the car 2 times last year). With AC on and the high temps here I like mine 185-200deg.

At any rate, I think a good electric fan, along with the stock shroud produces excellent results. My temperature drops amazingly quickly if I let the car get hot and then switch on mine. Hopefully you get yours sorted with your plan to move the rad back.

[varg]

The clutched fan with stock shroud will do a better job cooling than most of our E-fan setups, it moves a ton of air and is designed and tested to keep these cars cool in extreme heat, I'm not using it because there's no room and it will hit my radiator when the engine moves (BTDT). The turbo changes things a bit, it significantly heats the air in the engine bay. Air conditioning also makes a huge difference. Say it's 93°f here like it was yesterday, humidity ~%70, with the AC off (not happening) the air flowing through the radiator is 93°, with the AC on the air flowing through the radiator has been pre-heated by the AC condenser to over 120°f (I tested this). Add to that the fact that my intercooler is between my condenser and radiator hampering air flow and that's why I see temps over 200° with the AC on. I don't have room for a fan shroud or a bigger fan with the rad pushed back 3," something I'm hoping to change this weekend when I get the rest of the piping I need to move the IC (I hope). The thermostat isn't going to change anything here, a 75°C thermostat doesn't flow any more water than an 80°C or 88°C thermostat, it just opens earlier. Thermostat temp doesn't make a lick of difference once you're past it.

FWIW, 205°f is not overheating, even for these cars. Many cars are designed to keep coolant temps higher than that bone stock. 230°f is overheating.